The Allen-Bradley 1794-OW8 Flex I/O relay output module delivers eight isolated channels. It switches loads up to 250V AC at 2 Amps. This module uses normally open electromechanical relays for reliable operations. Engineers choose this module for its robust contact ratings. It handles pilot duty and resistive loads with ease. The module integrates seamlessly with Flex I/O systems. It controls actuators, valves, and other field devices effectively. This module provides a proven solution for discrete output control.
Product Procurement & Buyer Guide
Understanding the 1794-OW8 Output Architecture
The 1794-OW8 provides eight Form A (Normally Open) isolated relays. Each channel offers full electrical isolation from the others. This design prevents fault propagation across different output circuits. The module requires a 24V DC supply drawing 125 mA. It also draws 35 mA from the 5V FlexBus. You must use only +24V DC for the power terminals. Using other voltages risks relay timing variations.
Critical Relay Contact Ratings for Selection
The relay contacts handle a wide range of loads. For AC resistive loads, the rating is 250V AC at 2 Amps. For AC motor loads, the make rating is 1800VA and break is 180VA. For DC resistive loads, the rating is 2 Amps at 5-30V DC. The minimum contact load is 100 μA at 100 mV DC. This ensures reliable switching even for very low-power signals.
Terminal Base Compatibility and Wiring
This module requires a compatible terminal base unit. You can use the 1794-TB2, 1794-TB3, or 1794-TBN models. The 1794-TB3 offers three terminal strips for organized wiring. It supports daisy-chaining power to adjacent modules. The wire size depends on the chosen terminal base. Always check the terminal base manual for exact specs.
Environmental Tolerances and Durability
The module operates in temperatures from 0 to 55°C. It can withstand storage temperatures from -40 to 85°C. The unit resists vibration up to 5g at 10 to 500 Hz. It also handles operating shock up to 30 g. Each relay contact has a mechanical life of 100,000 operations. This ensures long service in demanding industrial environments.
Power Dissipation and Thermal Management
The module dissipates a maximum of 5.5 Watts of power. This equates to a thermal dissipation of 18.8 BTU per hour. Proper airflow around the module is important for heat removal. The module is an open-type enclosure for DIN Rail mounting. Ensure adequate spacing in the cabinet for cooling.
Keyswitch Position and Installation Safety
The module has a keyswitch position of 9. This mechanical key prevents inserting the wrong module type. It ensures safe and correct module installation on the base. Always align the keyswitch before mounting the module. This simple step prevents electrical damage and system faults.
Logistics & Standard Packaging Details
- One (1) Allen-Bradley 1794-OW8 Flex I/O Relay Output Module
- This module is an individual component without a terminal base.
- The product ships in anti-static packaging for safe transit.
- Express delivery shipping is available via FedEx, UPS, and DHL.
